With the development of electronic technologies, functions of display devices are no longer limited to receiving and displaying video signals. Nowadays, the display device has been integrated with a touch function, so that a control instruction can be input into the display device according to a touch operation performed by an operator on the display device.
The existing display devices with a touch function are divided into an add-on type touch screen, an on-cell touch screen, and an in-cell touch screen according to structures of the display devices. However, in any of the existing touch screens with the above various structures, touch signal lines connecting with touch electrodes are necessary. As shown in FIG. 1, each of the touch electrodes 10 is connected with one corresponding touch signal line 11. Generally, the touch signal lines 11 are arranged right below a black matrix of a color filter substrate to prevent the touch signal lines 11 from shielding light and being visible from outside. Thus, these touch signal lines 11 are relatively thin. For example, the touch signal line 11 has a width of 3 μm. However, such thin touch signal lines 11 are likely broken in fabrication, as shown by a region indicated by a dotted circle in FIG. 2, for example. Once the touch signal line 11 is broken, a touch on the touch electrode 10 corresponding to the broken touch signal line 11 cannot be responded to, thereby reducing the touch accuracy and negatively affecting the product yield.